The Design And Realization Of Extended System In Distributed Firealarm System Based On Microcontroller

It is no doubt that the happening of fire disaster does a great harm to the people. Inrecent years, people’s awareness of fire safety is continuously improved, and the number offire alarm control system applications has continued to increase. However, with ourcountry’s rapid economic development and strong commitment of urban construction,high-rise buildings and large resident area arising fast, which leads to the problem that themaximum number of nodes is not enough need to be solved.To solve the problems above, this thesis proposes to add an extended system betweenthe fire alarm controller and lower machine. By this way, it can increase the capacity of thesystem nodes and cabling distance. At the same time, it also can optimize the systemefficiency. The extended system uses a W78E516B single-chip as a microcontroller. And thethesis expands the RAM and Flash memory outside the single-chip. Each of the switchingplate has two CAN communication modules, which are used to communicate with the firealarm controller and lower machine.Firstly, this thesis briefly introduces the development of fire alarm technology. Then,the thesis analyzes the requirement and function of extended system, and come to the basicdesign principle of extended system. For CAN bus protocol doesn’t stipulate the applicationlayer, so the thesis focus on the design of CAN bus application layer based on theintroduction of CAN bus working principle. Subsequently, the article describes the hardwareand software design of extended system in detail. In the hardware design section, the thesisdivides the hardware into four functional modules to describe. In the software part, thethesis firstly gives the system software framework, and then focus on the design of driverprogram and application layer protocol analysis program. In the end, the thesis tests thefunction of extended system, and analyzes the testing result.